1. Field of the Invention
The present invention relates to a controller of a rotating electric machine for a vehicle using a winding type synchronous machine, particularly the controller of the rotating electric machine for a vehicle having a restraining function of a magnetic field electric current.
2. Description of the Related Art
The rotating electric machine for a vehicle is mounted to the vehicle and is used as a synchronous electric motor at a starting time of an internal combustion engine, and is also used as a charging electric generator after the internal combustion engine is started. In this rotating electric machine for a vehicle, it is required that the internal combustion engine is rapidly started by generating large torque as much as possible at the starting time of the internal combustion engine, and large generated electric power is supplied as much as possible from low speed rotation to high speed rotation after the internal combustion engine is started, and a battery mounted to the vehicle is charged while sufficient electric power is supplied with respect to a large electric load. In particular, it is required to obtain large generated electric power in the case of the large load even at an idle rotating time of the internal combustion engine.
To achieve such an object, a technique for optimally designing a rotator as a field magnet and improving a magnetic flux amount generated by the rotator is adopted in the general winding type synchronous machine. For example, the ampere turn of a field magnet coil of the rotator is increased as much as possible, and the magnetic flux amount is intended to be increased by simultaneously using the field magnet using a permanent magnet in the rotator of the winding type synchronous machine. In accordance with such a construction, the internal combustion engine can be rapidly started and a sufficient generated electric power output can be increased in a total rotating area. However, an excessive increase of the output in the high speed rotating area gives excessive stress to an electric power converter and the rotating electric machine itself. Therefore, there is a case in which it is necessary to restrain the ampere turn of the field magnet coil at the high speed rotating time.
In the technique disclosed in patent literature 1, the field magnet coil is simultaneously used in a magnet electric generator used in a compact two-wheeled vehicle. However, a magnetic field electric current at the high speed rotating time of the rotating electric machine functioning as an electric generator and a starting electric motor is controlled. When the rotating electric machine directly connected to a crank shaft is used as the electric generator, the upper limit value of an output electric current after rectification is set every rotating speed. When there is a possibility that the output electric current exceeds this upper limit value, this direct current output electric current is controlled so as not to exceed the upper limit value by controlling the magnetic field electric current. The magnetic field electric current controls the generated electric power output in a duty ratio by performing PWM control in accordance with the output electric current.
[Patent literature 1]
JP-A-2001-69797 (pages 4 to 5 and FIGS. 1 to 3)
In the above conventional device, the upper limit value of the output electric current can be also restrained by controlling the magnetic field electric current at the high speed rotating time. However, in the rotating electric machine mounted to the vehicle, its operation must be continued without causing any trouble due to an excessive electric current at all. Therefore, it is necessary to detect the excessive electric current of a line electric current in an alternating current electric path from the rotating electric machine as a multi-phase alternating current electric generator to the electric power converter, and precisely restrain this excessive electric current. Further, it is necessary to protect the rotating electric machine, the electric power converter and the electric path between the rotating electric machine and the electric power converter from deterioration.